Alarm watch



Sept 25, 1951 R. DlTlsHElM 2,568,795

ALARM WATCH Filed July 6, 1949 fllllflllnu..

Maf/MW /4 fw m@ PRIOR ART PRIOR ART Patented Sept. -25, 1951 ALARM WATCH Robert Ditisheim, La Chaux-de-Fonds, Switzerland, assignor to Ditisheim & Cie, Fabriques Vulcain et Volta, La Chaux-de-Fonds, Switzerland, a corporation of Switzerland Application July 6, 1949, Serial No. 103,305 In Switzerland July 17, 1948 12 Claims. 1

This invention relates to an improved alarm locking device of particular utility in an alarm Wrist Watch.

In ordinary alarms, the locking of the alarm mechanism is usually achieved by introducing a pin, or a point, into the trajectory of a member having a reciprocating motion. In most cases this member is constituted by either the anchor or the hammer of the alarm mechanism. The movable member can then be stopped by the pin either on one or the other side of the latter, the pin interruptingthe path of travel of the member and excluding it from access to a part of its trajectory. The excluded part of the trajectory is situated on one or the other side of the pin according to the position of the movable member at the instant when the pin is set in its locking position.

This known type of locking device has the disadvantage of permitting the movable member (anchor or hammer) to continue to oscillate through that part of its trajectory which will bring the hammer into contact with the sounding mechanism as the result of moving or jolting the time piece. This condition occurs when (a) the alarm mechanism is run down, and (b) the locking member or pin has happened to engage the movable member in one of two possible parts or segments of its trajectory. When this occurs there is no Way definitely to shift the movable member to the other side oi the locking pin While the latter is in locked position.

A principal object of the present invention is the provision of a locking member controlling the alarm mechanism, which, when in locked position, excludes the movable member (anchor or hammer) from a selected or denite part of its trajectory.

According to the invention as provided for an alarm watch having a hammer acting on a sounding member, the part of the trajectory selected for elimination may either correspond to the part of the trajectory of the said hammer in which the latter acts upon the sounding member in order to prevent the impact of the hammer upon the sounding member, or may correspond to another part of the trajectory of the said hammer which ensures that the remaining travel of hammer will not be sufficient for action of the hammer on the sounding member to cause an audible vibration. The watch can then be shaken without this resulting in the production of sound, even when the spring of the alarm mechanism is run down.

In a preferred embodiment of the invention,

capement driving a hammer which is integral with the said anchor. The locking member is constituted by a locking lever the extremity of which is situated, when in locking position, in the tra-y jectory of either the hammer or the anchor, in order to form a stop Which holds the said member in one direction but allows it to pass in the other direction. This result is obtained by giving the lever a shape designed to cause the extremity of the said lever to be elastically repelled by the movable member out of its trajectory when the said member moves in this latter direction, inclined cam-surfaces being provided on the movable member and on the locking member in order to facilitate the passage of the movable member.

The drawing shows, by way of example, two embodiments of the locking mechanism of a watch object of the invention, comprising a hammer driven by an anchor escapement and also,r

for comparison, a known form of such a mech.- anism.

Figs. 1 and 2 are plan and lateral views of the said mechanism in locked position.

Fig. 3 is a View similar to Fig. 2, wherein they anchor is situated opposite the locking member. Fig. 4 is a. section along the line IV-IV of Fig. 3.

Fig. 5 is a lateral view of a variant or modified anism comprising a hammer, driven by the anchor of an anchor escapement, which acts by percussion on a sounding member. escapement Wheel, the anchor and the locking member controlling the alarm mechanism, are shown.

The locking member is constituted by a locking lever I pivoted to a stop 2 and which can be placed either in a locking position in which its extremity 3 is situated in the trajectory of an anchor 4, as shown by Figs. 1 and 2 or in a retracted position in which its extremity is removed from the said trajectory. In this embodiment of the watch, according to the invention, the locking lever is subjected to the action of a release spring 5. Lever I is shifted to and from locked position by time controlled mechanism which acts upon its lower extremity 6. The anchor 4 is pivoted at 1, and drives a hammer, not shown, pivoted von the same axis as the anchor, by means Only the of a pin 8 integral with the hammer which penetrates into an aperture 9 cut in the said anchor. In its oscillating motion, one beak In of the anchor describes a trajectory comprised between the extreme positions al and a2 which are respectively shown by dotted and dot-and-dash lines on Figs. l and 2.

In locked position, the extremity 3 of lever l constitutes a stop excluding anchor 4 from part A2 of the trajectory of its beak l0, the beak of anchor 4 resting against surface Il of the bent extremity 3 of the locking lever, which lever Withstands buckling to restrain the anchor when the latter is applied against the locking lever owing to the escapement action. This resistance to buckling is sucient to bear the maximum pressure which is exerted at the termination of an energetic Winding of the alarm spring. When it -happens that locking lever l is brought to locking position (as shown by Fig. 2) at the interval when anchor beak is situated in part A2 of its trajectory, the extremity of lever l does not constitute a stop preventing the exit of the said beak from the said part of the trajectory, owing to the flexibility of the locking lever and to the inclined cam-surfaces l2 and I3 provided on extremity of the said lever and on anchor beak. The anchor moving in the direction of arrow B then repels the locking lever in the direction of arrow C, as shown by FigA 3, and can leave part A2 of its trajectory. This displacement of the anchor can occur in consequence of the motion of the alarm mechanism, or by movement of the hammer and the anchor when a jolt is imparted to the watch and the alarm spring is run down or, furthermore, under the action of an alarm locking such as a press-button (not shown) which would shift the anchor out of part A2 of its trajectory, for example by exerting a pressure on part i4 of the anchor.

In the embodiment shown, the excluded part A2 of the anchor trajectory is intended to represent the part of the trajectory of the hammer in which the latter strikes the sounding member. The disadvantage is thus prevented that the hammer, which is integral with the anchor, should repeatedly strike the sounding member under the effect of jolts imparted to the watch when the alarm spring is run down, which would cause an untimely noise. In fact, at its first oscillating motion, the anchor leaves the excluded part A2' and can no longer re-enter it owing to the locking member.

The excluded part of the trajectory can also correspond to the part of the hammer trajectory into which the latter is swung immediately before hitting the sounding member. In this case it is necessary that the trajectory part remaining available for the oscillation of the anchor and the hammer under the effect of jolts imparted to the watch should be sufficiently restricted in order that the hammer should no longer be able to hit the sounding member with enough violence to produce an audible vibration. Practically, the hammer must be maintained against the sounding member.

Owing to the right-angle design of the extremity 3 of the locking lever l and to the position of the said lever in a plane parallel to that in which the anchor 4 oscillates, the said lever will not buckle when acting as the stop, but is susceptible to bending when it is repelled backwards by the beak l0 of the anchor, as shown by Fig. 3. Locking lever l offers a slightly curved cross section in order to increase its resistance to buckling (see Fig. 4).

In another embodiment comprising the same members as the alarm-watch parts shown by Figs. l to 4, the modified locking member is constituted by a lever such as shown by Fig. 5. The extremity of the lever which, in the locking position, is placed in the trajectory of the anchor, is constituted by a member I5 pivoted at i6 on the extremity l1 of the locking lever. rIhe said member constitutes a pawl which is maintained in the position shown by means of a flat spring I8 fixed on the locking lever. In this variant the anchor is stopped by face I9 of the pawl when the latter moves downwards (as shown by Fig. 5) but, on the other hand, owing to the inclined surfaces i3 of the anchor and 20 of the pawl, it repels the pawl and can leave the part of its trajectory situated beneath the pawl, when it moves in the other direction. In this embodiment, no use is madeof any elasticity of the locking lever.

Figs. 6 and 7 show, by manner of comparison, an embodiment of a known locking member in which the locking lever bears a pin 2l which, in locking position, is brought into the trajectory of beak 22 of the anchor. In this arrangement the locking lever prevents the complete oscillation of the anchor but the anchor is positively held in one or the other of parts Al and A2 of its trajectory, determined by the pin and, when the alarm mechanism spring is run down, the anchor can oscillate over the extent of these parts of the trajectory.

If beak '22 is locked in that part of its trajectory including the hammer striking position, as soon as the alarm spring becomes run down, the hammer is free, despite the locking lever, to strike the sounding member an dthus to produce untimely noise.

On the other hand, such a locking member precludes the use of a return member allowing the anchor to be brought back, at will, to a definite position, for the anchor may be retained by the pin in a part of its trajectory which does not correspond to the said position.

What I claim is:

l. In an alarm mechanism for a timepiece, a pivoted movable member adapted to operate an alarm sounding means, means for imparting an oscillatory movement to said movable member, a locking member, means for moving said locking member into or out of contact with said movable member at a point within the path of its trajectory to confine the movement of said movable member, said locking member in locked position having a face providing positive locking means against movement of said movable member in one preselected direction but having means on its opposite face permitting said movable member to pass unhindered in the opposite preselected direction.

2. In an alarm mechanism for a timepiece, a pivoted escapement member adapted to operate an alarm hammer, an escapement Wheel for imparting an oscillatory movement to said escapement mechanism, a locking member, means for moving said locking member into or out of contact with said escapement member within the path of its trajectory to conne the movement of said escapement member, said locking member in locked position having a face resistant to the passage of said escapement member in one preselected direction, and having another face providing for the deection of said locking means i) from the path of said escapement member thereby permitting movement of said escapement member in the opposite preselected direction.

3. In an alarm mechanism for a timepiece, a pivoted movable member adapted to operate an alarm sounding means, means for imparting an oscillatory movement to said movable member, a locking member, means for moving said locking member into or out of contact with said movable member at a point in the path of its trajectory to confine the movement of said movable member, said locking member having a fiat surface in locked position opposing passage of said movable member when moved in one preselected direction, and having a cam surface in locked position permitting deflection of the locking member by said movable member when moved in the opposite direction, thereby permitting passage of the movable member in the said opposite direction.

4. In an alarm mechanism for a timepiece, a pivoted movable member adapted to operate an alarm sounding means, means for imparting an oscillatory movement to said movable member, a

locking member, means for moving said locking A member into or out of contact With said movable member at a point in the path of its trajectory to confine the movement of said movable member, said locking member having a fiat surface in locked position opposing passage of said movable member When moved in one preselected direction, and having a cam surface in locked position permitting deflection of the locking member by said movable member when moved in the opposite preselected direction, thereby permitting passage of the movable member in the said opposite direction, said movable member likewise having a cam surface complementary to the cam surface carried by said locking member.

5. The invention according to claim 3, wherein the locking member comprises a pivoted lever shaped to provide relative rigidity in resistance to pressure from the movable member in the said one preselected direction, and shaped for relative yielding resiliency to permit deflection by said movable member in said opposite direction.

6. In an alarm mechanism for a timepiece, a pivoted movable member adapted to operate an alarm sounding means, means for imparting an oscillatory movement to said movable member, a locking member, means for ,moving said locking member into or out of contact with said movable member at a point in the path of its trajectory to conne the movement of said movable member, said locking member comprising a pivoted lever having a tip formed at an angle to the body of the lever, the outer surface of said tip when in locked position presenting a iiat surface opposed to the passage of said movable member when moved in one preselected direction, and having an inner cam surface permitting deflection by said movable member when moved in the opposite preselected direction.

7. The invention according to cla1m 6, lthe body of said lever having a curved cross-section resistant to buckling,

8. The invention according to claim 6, the movable member likewise having a cam surface complementary to the cam surface on the tip of the lever and coacting therewith.

9. In an alarm mechanism for a timepiece, a pivoted escapement member adapted to operate an alarm sounding means, means for imparting an oscillatory movement to said escapement member, a locking device, means for moving said locking device into or out of :contact with said escapement member at a point within the path of its trajectory to conine the movement of said escapement member, said locking device comprising a pivoted lever and a pawl pivotally mounted on said lever, said pawl in locked position being braced against movement relative to said lever in one direction and resiliently movable relative to said lever in the opposite direction under the deflecting influence of said escapement member.

10. The invention according t0 claim 9, said pawl being resiliently movable relative to said lever by provision of a spring bearing on said pawl, said spring being yieldingly resistant to the deflecting inuence of said escapement member in the said opposite direction.

11. In an alarm mechanism for a timepiece, a pivoted escapement member adapted t0 operate an alarm sounding means, means for imparting an oscillatory movement to said escapement member, a locking device, means for moving said locking device into or out of contact with said escapement member at a point Within the path of its trajectory to conne the movement of said escapement member, said locking device comprising a pivoted lever and a pawl pivotally mounted on said lever, said pawl in locked position being braced against said lever to prevent relative movement in one direction, and being yieldingly movable against the inuence of a spring mounted for bearing on said pawl in the opposite direction, the tip of the pawl being angled to present a flat surface resistant to the passage of said escapement member in the direction against which it is braced, and having a cam surface assisting the deflection of the pawl by said escapement member in the direction in which yielding movement is provided.

12. The invention according to claim 1l, the said escapement member having a cam surface complementary to the cam surface of said pawl.

ROBERT DITISHEIM.

REFERENCES CITED UNITED STATES PATENTS Name Date Hodge Nov. 15, 1921 Number 

